code: def test_merge_from_json_does_not_overwrite_all_fields(self):
      # We want the "Limitations" field to be overwritten, but not "Users".
  
      # Initially, the ModelCard's "Limitations" and "Users" are specified.
      overwritten_limitation = model_card.Limitation(
          description="This model can only be used on text up to 140 characters."
      )
      not_overwritten_user = model_card.User(
          description="language researchers"
      )
      model_card_py = model_card.ModelCard(
          considerations=model_card.Considerations(
              limitations=[overwritten_limitation],
              users=[not_overwritten_user],
          )
      )
  
      # We create a JSON that specifies "Limitations" but not "Users".
      model_card_json = json.loads(_FULL_JSON)
      assert "limitations" in model_card_json["considerations"]
      assert "users" not in model_card_json["considerations"]
  
      # merge_from_json() overwrites ModelCard fields that were specified in JSON.
      # "Limitations" was specified, so it is overwritten, but "Users" is not.
      model_card_py.merge_from_json(model_card_json)
      self.assertNotIn(
          overwritten_limitation,
          model_card_py.considerations.limitations,
      )
      self.assertIn(
          not_overwritten_user, model_card_py.considerations.users
      )
  
imports: import json
  import os
  import pkgutil
  import jsonschema
  from absl.testing import absltest
  from google.protobuf import text_format
  from model_card_toolkit import model_card
  from model_card_toolkit.proto import model_card_pb2
label_desc: Use image node_id 11 for calling the ModelCardTest obj's underlying member method code with example usage: obj.test_merge_from_json_does_not_overwrite_all_fields() without return types